A Late Amazonian alteration layer related to local volcanism on Mars
- Research areas:
- Year:
- 2010
- Authors:
-
- Nicolas Mangold
- L. Roach
- R. Milliken
- Stéphane Le Mouélic
- Véronique Ansan
- J. P. Bibring
- Ph. Masson
- J. F. Mustard
- S. Murchie
- G. Neukum
- Journal:
- ICARUS
- Volume:
- 207
- Number:
- 1
- Pages:
- 265-276
- Month:
- May
- ISSN:
- 0019-1035
- Abstract:
- Hydrated minerals on Mars are most commonly found in ancient terrains
dating to the first billion years of the planet's evolution. Here we
discuss the identification of a hydrated light-toned rock unit present
in one Chasma of the Noctis Labyrinthus region. Stratigraphy and
topography show that this alteration layer is part of a thin unit that
drapes pre-existing bedrock. CRISM spectral data show that the unit
contains hydrated minerals indicative of aqueous alteration. Potential
minerals include sulfates such as bassanite (CaSO(4)center
dot(1)/(2)H(2)O) or possibly hydrated chloride salts. The proximity of a
smooth volcanic plain and the similar crater model age (Late Amazonian,
<100 Myr) of this plain and the draping deposits suggest that the
alteration layer may be formed by the interaction of water with ash
layers deposited during this geologically recent volcanic activity. The
alteration phases may have formed due to the presence of snow in contact
with hot ash, or eventually solid-gas interactions due to the volcanic
activity. The relatively young age of the volcanic plain implies that
recent alteration processes have occurred on Mars in relation with
volcanic activity, but such local processes do not require conditions
different than the current climate. (C) 2009 Elsevier Inc. All rights
reserved.
